Microinjector



Jan. 20, 1942. s DUTKY ETAL 2,270,804

MIGROINJECTOR Filed July 18, 1940 2 Sheets-Sheet 2 SAMSON R. DUTKY WILLIAM c. FEST ihmenfors M 6 g I W Gttornegs Patented Jan. 20, 1942 UNITED STATES PATENT 1 OFFICE MICRO INJECTOR Samson R. Dutky, Palmyra, and William C. Fest, ,Masonville, N. J dedicated to the free use or the People in the territory of the United States Application July 18, 1940, Serial No. 346,155

(Granted under the act of March 3, 1883, as

*amended April 30, 1928; 370 0. G. 757) 3 Claims.

This invention relates to an instrument designed to deliver accurately predetermined volumes of liquids for the purpose of making hypodermic injections.

In general, the invention comprises a hypodermic syringe of the plunger type and a micrometer screw adapted to actuate the plunger of the syringe, means being provided to determine relative positions of the micrometerscrew as a function of the volume of liquid delivered.

In the accompanying drawings, thereare illus-' trated three embodiments of my invention, in

which: c

Figure 1 is a plan view of the simplest embodiment.

Figure 2 ment.

Figure 3 is an end view of Figure 2.

Figure 4 is a side elevational view of Figure 2.

Figure 5 is a plan view of the third, and preferred, embodiment of my invention.

Figure 6 is a side elevation of Figure 5. I

Figure 7 is a longitudinal section along the line 1--1 of Figure 5.

Referring with more particularity to Figure 1, the embodiment illustrated comprises a suitable base 10, upon which is removably mounted an ordinary hypodermic syringe ll of the plunger type. The plunger of said syringe is designated by the numeral I2 and the needle and coupling therefor by the numeral 13. The barrel of the syringe II is seated in a groove 14 of a block l5 transversely mounted on the base Ill, the flange l6 of the syringe abutting the said block I5, substantially as shown A hinged flap I1 is mounted on the block l5 so as to hold the syringe in place in the groove l4. To the rear of block l5, there is horizontally secured a U-shaped bracket l8, through the rearward arm of which a micrometer screw I9 is threadedly engaged in line with the plunger 12. Between the plunger I2 and the end of the micrometer screw IS a spacing bar is disposed through the other arm of the bracket l8. The spacing bar is mounted so that it will not is a plan view of the second embodirotate, under the influence of the micrometer screw 19. .The micrometer screw I9 is actuated by a cylinder 2 I, to which it is secured, said cylinder operating over a barrel 22 fixed to the bracket any errors which might resultfrom such rotation are prevented. i I

The embodiment illustrated in Figures 2, 3, and 4 employs substantially the same partsas that illustrated in Figure 1 except that means are added to permit the operator to actuate a lever and thereby cause the device to deliver apredeterminedvolume of liquid without reference to the scales 23 and 24. In this embodiment a ratchet wheel 25 is secured to the cylinder 2 I A pawl 26 is associated with the wheel 25 and is mounted between two arms 21, 2'? straddling the wheel 25. The arms 21, 21 are hinged to arms 26, 28 of a shaft 29. Saidarms are secured together for coaction by means of a rod 30.

The shaft 29 is rotatably mounted in suitable bearings 3|, 3| fixed to the base of the instrutherewith. In order to prevent a return movement of the wheel 25 after the pawl 26 has been actuated downward and released, a yieldable abutment, such as a U-shaped bar 36, is mounted on the base of the instrument in contact with the wheel 25, preferably on the side opposite the pawl 26. By changing the size of the wheel 25 or the number of teeth thereof, or by changing the position of the abutment pins 33, variations in the quantity of liquid ejected on each stroke of the arm '32 may be accomplished.

Referring with more particularity to Figures 5,

6, and '1, which illustrate the third, and preferred, embodiment of my invention, the same general ararngement of parts is employed as in the first two embodiments with respect to the syringe and the micrometer screw, except that the spacing bar is omitted. The micrometer screw 31, in this preferred embodiment, is held in a nonrotatable position by means of a longitudinal groove 38, engaging 'a guide pin 39. The micrometer screw is slidably disposed through apertures 40 and 4| of a pair of mounts 42 and 43, respectively, longitudinally aligned with respect to the syringe II, and the guide pin 39 is disposed wheel to rotate a given distance, which, in turn, causes the micrometer screw 31 to be propelled forward against the plunger of the syringe. Upon release of the bar 54, the springs 59 return both of the bars 54 and 55 to their normal positions together withthe pawl 51, the ratchet wheel being held stationary by means of the abutment 60. The movement of the screw 31 urges the plunger inward and causes the delivery of a given amount of liquid for each stroke of the arm 54. When it is desired to replenish the supply of liquid in the syringe, the syringe is removed, reloaded, and replaced in the instrument.

through one of the mounts 43 and held .in place by means of a spring 44 mounted for tensioning between a shouldered portion 45 of said pin and the upper flange 45 of a sleeve fitting 41 secured to said mount 43. The rearward end of the screw 31 terminates in a shaft 48 which projects beyond the mount 43 and is provided with a knurled surface 49 to permit easy manual rotation of the screw when the guide pin 33 is disengaged from the groove 38.

Between the two mounts 42 and 43, the ratchet wheel 50 is disposed about the screw 31, the hub of said wheel being threadedly engaged with said screw and flanged so as to fill up the space between the two mounts at that point. By these means, when the ratchet 'wheel is rotated, the micrometer screw 31 is translated through the apertures 40 and 4|, the guide pin 39 preventing the screw from rotating. A U-shaped bar similar to the shaft 29 illustrated in the second embodiment, is disposed on the base of the instrument, the web thereof being pivoted in longitudinally disposed bearings 52 and 53. One arm 54 of the bar is disposed beneath the syringe on the forward part of the instrument, and the other arm 55 is disposed beneath the ratchet wheel 50. To the arm 55 there is hinged an assembly 56, including a pawl 51 adapted to engage the teeth of the ratchet wheel 50. A spring 58 is disposed between the pawl 51 and the arm 55 and so tensioned that it urges the pawl against the ratchet wheel. Springs 59 are provided between the base of the instrument and the bottom of the arms 54 and 55, respectively so as to'urge and normally hold said arms in an elevated position, whereby when the arms 54 and 55 are depressed, they are automatically returnedto their normal position. A yieldable abutment 60 is also provided in association with the ratchet wheel, simi lar to the member 35 in the second embodiment illustrated.

When the arm 54 is depressed, the pawl 51 is actuated downward, thereby causing the ratchet However, upon replacement it is necessary to retract the micrometer screw 31 to make room for the extension of the plunger. To accomplish such a retraction, the guide pin 39 is elevated against the action of the spring 44, thereby permitting the micrometer screw 31 to rotate. The shaft 48 of the micrometer screw is then rotated in the same direction in which the ratchet wheel is normally operated, while the ratchet wheel is held in a fixed position. 7

Having thus described our invention, we claim:

1. A microinjector comprising a base structure, means for removably securing a. plunger actuatable syringe on said base, a micrometer screw for actuating the plunger of said syringe, a ratchet wheel secured to said screw, a pawl for unidirectionally engaging said ratchet wheel, means for actuating said pawl, and means for limiting the movement of said pawl so that each time said pawl is fully actuated said screw is moved a predetermined distance.

2. A microinjector comprising a base structure, means for removably securing a plunger actuatable syringe on said base, a micrometer screw for actuating the plunger of said syringe, a

ratchet wheel threadedly engaged with said screw, axial abutments for said wheel, means for holding said screw is a non-rotatable position with respect to said plunger, a pawl for unidirectionally rotating said ratchet wheel, and means for actuating said pawl. 3. A microinjector comprising a base structure, means for removably securing a plunger actuatable syringe on said base, a micrometer screw for actuating the plunger of said syringe, said screw having a longitudinal groove, a ratchet wheel threadedly engaged with saidscrew, axial abutments for said wheel, a removable pin engaging said groove to prevent rotation of said screw, a pawl for unidirectionally rotating said ratchet wheel, and means for actuating said pawl.

SAMSON R. DU'IKY. WILLIAM C. FEST. 

